The objective of this study of blood rheology and hemodynamics in normal and pathological models is a collaborative interdisciplinary effort to characterize the biochemical and physical properties of blood cells, their membranes and adhesive molecules, as these properties have significance to maturation of erythrocytes and leukocytes; contribute to flow behavior in the microcirculation; and as they pertain to microvascular inflammatory response and occlusive phenomena. The efforts focus on the physiological processes of cell maturation and activation, flow in the microvasculature (including cell adhesion to endothelium, and occlusion), and transport of oxygen, and combine the experimental approaches to issues of clinical importance with analytical and theoretical contributions of engineering scientists and biophysicists. Model disorders for study include sickle cell disease, hereditary spherocytosis, diabetes, leukemias and vaso-occlusive disorders. The proposed projects include: (1) Investigations of the interactions of adhesion molecules with blood cell and endothelial cell surfaces, under flow conditions, and the adhesion processes; (2) Studies of the mechanical properties of maturing blood cells and how they affect blood microcirculation; (3) Examination of control mechanisms of microvascular blood flow, including responses to the presence of altered blood cells; (4) Development and utilization of realistic mathematical models of microvascular blood flow; and (5) Extension of model and theoretical studies of studies of microcirculatory flow to provide hydrodynamic bases for interpreting observed cellular interactions. Three core units provide administrative functions, a flow cytometry laboratory service, and a comprehensive image analysis system.